Why does he always ask me out at the last minute?

I have been talking to/seeing this guy for nearly a month. He calls and text me every day. He seems to show a genuine interest in me and my life he ask me about certain things that is going on in my life if I mention it to him. He's an all around great guy...But he never plans a date with me he'll just call me up some days and ask me if I want to go out with him somewhere. And naturally I say yes as I do want to hang out with him. But this seems to be turning into a repetitive pattern.

Like he asked me last night if I would be doing anything Friday (today). I told him that I had something going on with my friend possibly. Well he said that he had a POSSIBLE date with some of his friends but if they flake out on him he would love to hang out with me if my friend and I don't hang out as planned. The thing is he doesn't know if his friend still wants to hang out with him so he is basically going to wait around to see if they'll ever get back in contact with him to determine if they will hang out. If not he'll call me up. Now I wouldn't have a problem with this if he hadn't done this before...but he has just last weekend.

He always ask me at last minute las this past Monday he asked me out and we just hung out at McDonald's most of the night looking up funny stuff on his laptop which was nice. I know he's not with me just for sex that's for sure.

So should I be concerned with his spontaneous behavior is it a sign that he may not be ready for a committed relationship?